chore: remove extension points render/update extended profile fields in the account settings

[BryanttV]

Description

This PR removes the extension points responsible for rendering and updating extended profile fields in the account settings:

• NAU_STUDENT_ACCOUNT_PARTIAL_UPDATE
• NAU_STUDENT_SERIALIZER_CONTEXT_EXTENSION
• NAU_STUDENT_ACCOUNT_CONTEXT_EXTENSION

Also removes the NAU_ACCOUNTS_CC_VISIBLE_FIELDS settings since the context_extender.py was removed. From now on, these fields will be defined in the extended_profile_fields setting in the Site Configurations.

{
    "extended_profile_fields": [
        "employment_situation",
        "allow_newsletter",
        "nif"
    ]
}

Note

For changes to the Site Configurations to work correctly, the following implementation (fccn/edx-platform#30) must be used.

Related Issues

https://github.com/fccn/nau-technical/issues/394

Related PRs

• revert: remove extension points to get/update extended profile fields in the account settings edx-platform#29

[sandroscosta]

@BryanttV
So this PR you are working on will the one responsible for removing all the duplication in the platform, am I right?